On the minimal number of components of fixed point sets
Zhao, Xuezhi
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Nielsen number $N(f)$ serves as a lower bound for the number of
fixed points of self maps in the homotopy class of the given map
$f\colon X\to X$. It is also a lower bound for the number of
components of fixed point sets of all such maps. But, in general,
the relative Nielsen number $N(f;X,A)$ is not a lower bound for the
number of components of fixed point set of the maps in the
relative homotopy class of $f\colon (X,A)\to (X,A)$.
In this paper, we introduce a new relative homotopy invariant
$N^C(f;X,A)$, which is a lower bound for the number of components
of fixed point set of the maps in the relative homotopy class of
$f\colon (X,A)\to (X,A)$. Some properties of $N^C(f;X,A)$ will be
given, which are very similar to those of $N^C(f;X,A)$.
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